A practice now common in the telephone industry is to provide a subscriber, typically a business or commercial entity, with a single telephone number to serve diverse geographical areas or territories. Calls placed to that number are routed to respondents who are appointed to serve the respective areas from which the calls originate. While the terminology may differ, depending on the exact context, the single telephone number is sometimes referred to as a "virtual" number since it represents no telephone station in particular, but rather is the calling number for a plurality of stations, each of which may have its own actual directory number.
Virtual numbers have been used in a long-distance context whereby a single number is promoted on a large scale, typically nation-wide, and calls to the number are carried by an inter-exchange, or long distance carrier. The number for these wide area services is usually a special service access number such as an 800 or 900 number, depending on whether the called party or the caller is to be responsible for the call charges. The prior art is predominantly directed to handling calls received on a wide area basis and from areas whose boundaries are rather static and predefined.
A patent to Weber, U.S. Pat. No. 4,191,860, for example, discloses a system whereby a caller dials an 800 number, which, along with the caller's area code (i.e., the NPA, or numbering plan area code), is then used to access a translation table stored in a database system and retrieve an ordinary telephone number to which the call is consequently routed. This is the so-called WATS to POTS translation (Wide Area Telephone Service to Plain Old Telephone Service), now widely deployed by interexchange carriers in a variety of forms. Since the NPA is indicative of a certain geographical area from which the call originates (there are some 200 NPAs in the country), the translation can be made to yield a POTS number for a party who is especially suited to respond to calls that originate from that area. Thus, callers from different areas, as determined from their area codes, may be routed differently. This arrangement is adequate only if all calls from the same area code are to be routed to the same destination.
Another patent, U.S. Pat. No. 4,757,267, to Riskin, discloses a system that directs an 800 call (the dialed digits of which uniquely identify a product or service) to a dealer in those goods or services who is located in some proximity to the calling station. From knowledge of the originating telephone number the call is first routed to a service company in the general vicinity of the caller. A vertical-horizontal (V-H) file, equivalent to latitude and longitude, locates each dealer and the calling station so that a comparison of their V-H coordinates determines the dealer who is closest. Once the nearest dealer is determined, that dealer's telephone number is dialed automatically. Alternatively, Riskin suggests use of a database according to the Weber model whereby that database, upon being queried with the 800 number and the NPA, sets up a call to another database, providing to it the dialed 800 number and the calling station's NPA and exchange code. Again, from the respective V-H coordinates, the second database system determines the nearest dealer and the POTS number is returned through the facilities associated with the first database for call completion. The focus of the Riskin patent is on getting the long distance caller to the dealer who happens to be closest even though that dealer may not be the dealer assigned to a predefined territory.
A patent to Wegrzynowicz, U.S. Pat. No. 5,136,636, also routes calls to local dealers by building upon the use of a Weber type of database. In operation, a caller dials the virtual 800 number (ten digits) and a primary database (i.e., the Weber database) is accessed using the NPA of the caller and the 800 number; the output of the primary database is a number that identifies one of a plurality of secondary databases for a customer, and a key identifying the customer, for access. That information is then returned from the database, through the associated signaling system, to a network screening office. A translation is made to determine which secondary database of the customer to access. The access key plus the first six digits of the caller's directory number or the entire number is then cross-referenced to a local dealer telephone number, which is returned to the switching system of the network for call routing. As with the system upon which this is built (i.e., the Weber system), the process starts with an 800 number and an input indication of the calling station's location.
Notably, this latter patent expressly recognizes that, only under special circumstances are these techniques applicable for intra-LATA or local services. In particular, the patent notes that "If nationwide 7-digit numbers (for example, numbers beginning with 950) can be allocated for a limited number of dealers, then this service can also be provided as an Intra Local Access and Telephone Transport Area (Intra-LATA) call . . . " (Col. 6, lines 19-23). The described service is applicable locally only with the assignment of special numbers.
Despite the prior focus on wide area service, however, there is also a need for techniques which will facilitate somewhat more localized virtual number usage and which will be particularly adaptable to prescribe call routing from territories whose boundaries are subject to change from time to time. As an example, a hypothetical pizza franchise chain, operating across a wide geographic area or even nationally, may promote a single 800 telephone number for customers anywhere within the area to call. When the number is called, the customer is put in touch with the local pizza outlet. There is also a demand for this kind of call routing service on a localized, intra-LATA, basis (i.e., non-long-distance) so that calling customers only have to dial what appears to be a typical seven digit telephone number, and not necessarily an 800 or 900 special service access number. Thus, expressed in terms of the pizza chain example, instead of operating nationally, the pizza establishment may operate only in a single metropolitan area and have localized outlets therein whose territories are expected to be defined, not necessarily by area code, but by streets and local addresses. Desirably, these outlets would all be served by a single metropolitan seven digit phone number such that each outlet receives calls that originate in its assigned territory and such that the boundaries of the assigned territories can, for the call routing service, be established and redefined as required for serving changing needs of the establishment.